1. Field of the Invention
The present invention relates to a method for writing data onto a disk of a hard disk drive.
2. Background Information
Hard disk drives contain a plurality of magnetic heads that are coupled to rotating disks. The heads can magnetize and sense the magnetic fields of the disks to write and read data, respectively. The heads are coupled to a pivoting actuator arm that has a voice coil motor.
Data is typically stored on tracks that extend radially across the disk surfaces. The voice coil motor can be energized to pivot the actuator arm and move the heads to different track locations. Each track is typically divided into a number of sectors. Each sector contains at least one data field.
The disk drive typically writes data in blocks across a number of data sectors. Data is written by providing a write current to a coil of each head. The coil generates a magnetic flux that magnetizes the disk. Conversely, data is read through a read element in the head that sense a magnetic field provides a waveform to a pre-amplifier. The waveform is digitized and processed into a series of bits.
The read/write signal is processed using a number of read/write channel parameters. By way of example, there may be read channel parameters like cutoff frequency, gain, and boost; and write channel parameters like write current, overshoot, and write pre-compensation. Head characteristics may vary between heads. To compensate for this variation the heads are typically tested to optimize the read/write channel parameters.
Historically read/write channel parameters are optimized one parameter at a time. This is a time consuming step in test process. Additionally, some of the parameters are interdependent so that varying one parameter may change the optimum value for another parameter. This increases development time to understand and deal with the interdependence effect. It would be desirable to provide a process to optimize read/write channel parameters that is efficient and accounts for co-dependency between parameters.